2017 KTM 250 SX

Fireball

• ENGINE: The engine of the 250 SX has been known and respected for being the most powerful 2-stroke engine in its class. But we thought the segment could use an extra push and a solid statement: 2-strokes have a future at KTM. Their outstanding power-to-weight ratio, low cost and simplicity see to that. Putting our money where our mouth is, we gave the 250 SX engine an all new architecture with a new shaft arrangement for better mass centralization, a new cylinder with a twin-valve controlled power valve, a new counter balancer for less engine vibrations, a 5-speed transmission and a hydraulically operated DDS clutch. This compact fireball truly outshines the competition with absolutely ripping performance and is the right choice for lovers of premix.
• CYLINDER: The newly developed cylinder of the 250 SX - with a bore of 66.4mm - has all-new ports and is fitted with an overhauled power valve system. This system features a sophisticated mechanism for the lateral support exhaust ports, providing smooth and controllable power on tap. Furthermore, it’s possible to change the bike’s power delivery in seconds thanks to two supplied powervalve springs. Limitless settings for different tracks and preferences are up for grabs. Throw everything you have at it; new water jackets in the cylinder and head will take care of excess heat and reworked lateral cylinder head brackets allow a more efficient fixation of the engine to the frame via lightweight head stays. Yes, this is a serious piece of kit.
• ENGINE CASES: These all-new die-cast engine cases feature an 8mm higher clutch shaft and a 27mm higher crankshaft, resulting in better mass centralization and quicker handling. In addition, it allows the implementation of a counter balance shaft. So your ride will be as relaxed as it is rapid. Plus, your new favorite engine will keep looking as fresh as the day you bought it with redesigned engine covers featuring a smart surface structure in order to reduce the wear caused by the rider’s boots.
• TRANSMISSION: This reworked 5-speed gearbox has the same gear ratios as its predecessor, but our engineers took a close look at the mechanism in order to provide you with more precise and easier shifting. An advanced ´No Dirt´gear lever design prevents mud from clogging the folding tip for reliable shifts even in the worst conditions.
• COUNTER BALANCE SHAFT: Say goodbye to numb feet and hands. The new engine design allows the implementation of a lateral counter balance shaft in order to reduce the vibration level drastically - 50% lower level on handlebar and foot pegs. You know what that means: less fatigue at the end of the moto so you can push when it really counts.
• CLUTCH: The 250 SX employs the KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket and extremely heat resistant clutch plates. This clever design employs a diaphragm spring instead of the usual coil springs, making for considerably easier clutch action. A diaphragm spring also leaves sufficient space for a damping system to be integrated into the clutch hub. The goal is traction, but durability is as well. A lighter basket, a reworked inner hub and a pressure plate providing better oil supply and unsurpassed cooling up the longevity of the DDS clutch. Light operation and telepathic amounts of control are standard with this hydraulic Brembo actuated clutch.
• CARBURETOR: As of model year 2017, all KTM 2-stroke models are fitted with new MIKUNI TMX carburetors. These 38mm flat slide carbs provide smooth and controllable power all the way up to the limiter. And they’re less sensitive to altitudes and temperatures changes, so you can pin it wherever, whenever.
• EXHAUST: The engineers meticulously tuned the expansion chamber for maximum power. An advanced 3-D production process now guarantees higher precision manufacturing for a strong pipe that provides perfectly tuned power.
• CRANKSHAFT: Its 72mm stroke is the same, the rest is brand new. The 250 SX’s crank has been rebalanced, revamped and set-up with a counter balance shaft to kill vibrations, not your vibe.

Slim and Smart

• FEATHERWEIGHT: KTM engineers just love dropping weight year after year. The result: the 2017 SX models are the slimmest, lightest dirt bikes out there.
• FRAME: The high-tech, lightweight chrome-moly steel frame is engineered for excellent handling, precise cornering and supreme stability. You can also count on high torsional rigidity and low longitudinal stiffness for better absorption of the energy created by the front and rear suspension sucking up jumps and bumps. In short: more comfort and less rider fatigue. Laterally attached, lightweight engine head stays contribute to a reduced vibration level. The engineers were able to pull off all that, while making the frame two pounds lighter than that of the lightest competitor on the market. In addition, the frame is easier to maintain, easier to work on and supplies more space for the tank and other components. The bike also features an extra-light aluminum subframe, which weighs in at less than 2 pounds.
• FOOTPEGS: Sophisticated ´No Dirt´ footpegs prevent smudging up the pegs, even when digging in deep ruts. Looking for a higher riding position? Then just mount the footpegs of the MY2017 EXC models, which are 6 mm higher than the SX versions.
• AIRBOX: The airbox design offers maximum protection of the air filter while ensuring maximum airflow. The large twin-air filter is mounted in a stiff cage, which at the same time holds the system in place. This design is so simple you could still pop a fresh one in with a face full of mud. Without tools. In seconds.
• HANDLEBAR: KTM engineers sure know how to handle handlebars. This tapered one, made of high-strength aluminum by NEKEN, is fixed in damped rubber mounts and has two different positions. From 2017 onwards, the lower handlebar clamps are separated, while on the upper side a new bridge-type clamp guarantees more torsional stiffness. It’s also easier to replace the bar in case it gets twisted in a nasty crash. ODI lock-on grips make grip changes easy which does not require any wire or glue to be secured.
• SWINGARM: The cast aluminum design offers low weight and a perfect flex behavior. The single-component casting process eliminates any inconsistencies and inherent weak points created by welding. It’s better looking as well.
• FUEL TANK: A lightweight polyethylene tank has a capacity of 1.85 gallons. The filler cap has an inside thread, which makes for easy and reliable closure.
• WHEELS: Featuring lightweight, CNC machined hubs and high-end Excel rims, they guarantee maximum stability and minimal unsprung weight. The wheels are shod with the latest Dunlop Geomax MX 3S tires.
• SEAT: Tailored to meet the needs of the world’s fastest racers, this durable seat offers great comfort. For 2017, a new cover gives its riders even more grip with better feel.
• COOLING SYSTEM: KTM’s proven cooling system routes the coolant from the cylinder head through the frame triangle, directly to aluminum radiators made by WP. A new filler cap system and are stiffer alloy construction increase the durability and reliability of the cooling system. Due to flow optimized internal circulation and CFD-calculated air ventilation, the system is superbly efficient. In addition, well thought-out radiator guards integrated in the front part of the shrouds provide protection in a crash.

Striking Good Looks

• BODYWORK: KTM R&D, Kiska Design and the factory racers had their say in shaping the plastics with one goal: complete harmony between rider and bike. Perfect ergonomics and contact points provide maximum comfort in movement on the SX-F. The I-beam structures of the front and rear fenders guarantee maximum stability and a low weight thanks to well thought-out construction and mounting. They also stay cleaner for longer.
• GRAPHICS: New graphics convey the READY TO RACE character of the 2017 SX model line.

World-Proof

• MONOSHOCK: The WP monoshock has been developed with the entire frame and swingarm architecture in mind, including the linkage system and the WP AER 48 front forks. It features machined and black anodized components and is a valuable, high-end product compared to roughcast reservoirs. A new setting and a softer spring perfectly match the reworked front-end set-up and its sparkling WP color scheme lets everyone know you have excellent taste in suspension.
• FORKS: The lightweight WP AER 48 front fork, a 48mm USD air-sprung fork developed by WP in close collaboration with KTM, is a split fork with separate functions for each leg. That means damping functions are on the right side, whereas the air spring is in the left. This left leg features a two-chamber system with a capsuled air cartridge to prevent loss of air pressure. The air spring is easy to adjust to any rider weight via a single air valve. No special tools are required; just the air pump provided with the bike. The right fork leg integrates a damping cartridge that tailors to all your damping needs. It can be adjusted to the track conditions and the rider’s preferences with a twist of a dial (compression from the top, rebound from the bottom, 30 clicks each). For 2017, the AER 48 also features redesigned outer tubes with better flex characteristics, smoother operation and less friction. And they are 3 pounds lighter than the 4CS units they replace. Right off the dealer floor, these forks are more comfortable and more sensitive than ever. But you can still hammer the hell out of them.
• TRIPLE CLAMP: Top quality, CNC machined triple clamps have been a KTM trademark for years to ensure precise handling. For 2017, the upper triple clamp specifically features a redesign in conjunction with the new fork tubes. The rubber damped handlebar mount has also been reworked and the lower handlebar clamps are now separated, while on the upper side a new bridge-type clamp guarantees more torsional stiffness and can easily be replaced in case it gets twisted due to a crash. In addition, an hour meter is fitted at the upper triple clamp in order to let the rider know it’s time for a service.
• BRAKES: You can’t brake any harder, better, faster or stronger. These high-tech Brembo babies are combined with lightweight wave discs made by Galfer. For 2017, the rear brake features a 10mm longer brake pedal and you get new, less aggressive brake pads all round.